Addition agent for lubricating oil and method of making same



Patented May 23, 1944 ADD ITION AGENT FOR LUBRICATING OIL AND IMETHOD OFMAKING SAME Raymond Renter, Medici-d Lakes, N. J., assignor to TheAtlantic Beflnln g Company, Philadelphia, Pa., a corporation ofPennsylvania No Drawing. Original application February 20,

1940, Serial No. 319,839.

Divided and this all-' plication December I, 1940, Serial No. 369,120

6 Claims.

This invention relates to the treatment of hydrocarbon products such asmineral oils to improve their characteristics, and particularly to theaddition to petroleum lubricating oils of certain materials whichimprove their ability to resist the deteriorating effect of oxidationand their ability to lubricate bearing surfaces which are subjected toextreme pressures such as are now commonly encountered in the newertypes of machinery.

This application is adivision of my application Serial No. 319,839,filed February 20, 1940, entitled Lubricant. I

Moderately refined oils, such as motor oils and other moderately refinedlubricating oils and moderately refined turbine oils normally usedunderconditions of exposure to oxidation in the presence of metals, oxidize,giving rise to sludge and/or acidic oxidation products frequentlycorrosive to the metals which they encounter in use, as for examplebearing metals in automotive use,

p and copper and copper alloys in turbine use. It

has now been found that stabilization of these oils against suchoxidation effects may be conveniently accomplished by addition to theoils of,

formation of sludge and/or acidic constituents and the like under normalconditions of use.

Recent changes in automotive engine design, tending toward higherbearing pressures, higher rotative speeds, higher engine temperatures,and the like, have occasioned departure from the use of the usualbearing metals such as babbitt. The

newer bearing metals are of different nature,

than those less recently developed and while harder, are in general moresusceptible to destructive agencies of a corrosive nature. Typical ofthese newer bearings are those composed of a cadmium-silver alloysupported upon a steel back, which are now widely installed in certainmakes of automobiles. Others of these relatively new bearing metalswhich may be mentioned are copper-lead alloys, copper-lead-tin alloys,cadconcurrent with marked advances in methods of refining lubricant oilsfor automotive use. The demand for oils having lesser changes inviscosity with temperature change; i. e., higher viscosity index(frequently designated as V. I.), has been met by refining lubricantsintended for motor oils by certain solvent refining or solventextraction processes, whereinadvantage is taken of the-selective solventpower. for hydrocarbons of various types which is possessed by certainliquid reagents, for example, dichlorodiethylether, cresylic acid,phenol, chloraniline, chlorophenol, phenetidine, benzyl alcohol,nitrobenzene, benzonitrile, furfural, aniline, benzyl acetate, liquidsulphur dioxide, mixtures of liquid sulphur dioxide or aniline withbenzol, and the like. Those solvent refining processes are designed toconcentrate in the desired lubricant fraction those compounds of aparaifinic nature possessed of the ability to sufier only a small changeof viscosity with changeof, temperature, and to reject the compounds ofnaphthenic nature which do suffer such change of viscosity to a markeddegree. These refining processes have provided a supply of oil of quitedesirable general characteristics,

definitely far superior to any oil previously produced from'mixed baseor asphaltic crudes, and superior to a like, though lesser, degree overoils previously produced from parafiin base crudes.

It has been found that the solvent refined mo- ,tor oils referred toabove are definitely corrosive to the newer bearing metals referred toabove under extreme conditions of automotive use, due to oxidationduring use, sometimes resulting in bearing failure after only a fewthousand miles of driving. Difficulties are frequently encountered dueto bearing corrosion in automotive equipment operated at sustained highspeeds of theorder of to M. P. 1-1., or under other mium-nickel alloys,cadmium-zinc alloys, cad- .mium-zinc .alloys'modified by the presence oflead, antimony, or both, and a general class of' alloys consistingmainly of lead and hardened with calcium, barium, potassium,antimonsuand the like, known generically as high lead babbitts. Y "Thesechanges in engine -design have been 55 kind referred'to above.

conditions conducive to high crankcase temperatures of the order of 275F. or higher.- It is further known that the same reaction, viz.,corrosion of alloy bearing metals such as cadmium-silver, also occursingood parafiinic base oils which have not been subjected to solventrefining. The higher the V. I. ofthe lubricating 'oil, the morepronounced is the tendency to corrosion of the Generally speaking, the

problem is encountered in oils having a V. I. of

or'higher, particularly at elevated temperatures of engine operation.

Furthermore, the present trend in automotive design toward lower bodystyles, rapid acceleration, and the use of hypoid gears has increasedthe unit loadings on rear axles. In some-cases making use of thelubricants so produced.

, cosity index. It is also an object of this inven- Aiurther object ofvision of lubricating oils, particularly'oils for use the unit pressuresencountered become great enough to rupture the oil film of ordinarymineral oil lubricants, with consequent metal to metal contact. In otherlines of power transmission and the like, there is a similar tendencytoward. 5 the use ofhigh unit pressures of a degree which are near orbeyond the limit at which mineral oils, alone, will maintain efiectivelubrication. This invention is therefore specifically concerned with theproduction of lubricants capable of i0 withstanding the high unitloadingswhich occur in such instances. Such lubricants are generallyspoken of as extreme pressure lubricants.

' Extreme pressure lubricants are normally produced by adding to ahydrocarbon lubricant a is small amount of some characterizing substancewhich enables it to maintain a lubricant film unruptured underconditions which-would cause the breakdown of a film formed of,oilaione.

, Such additive substances are spbken oi as E. P.

(extreme pressure) bases, or E. P. ingredients. Many commonly used E. P.bases are composed of sulphur dissolved in mineral oil, sulphurizedvegetable or animal oils, chlorinated compounds, metallic soaps, and thelike. This invention is specifically concerned with the use as E. P.characterized ingredients, of compounds new and novel for this e, andnot heretofore so used or known to be useful for this purpose. 0

It is an object ertins invention to provide an extreme pressurelubricant, which lubricant is superior to lubricants of this classheretofore commonly known, particularly in load-carrying capacity,stability, and maintenance of extreme pressure lubricating propertiesunder sustained conditions oi. high 10 It is an object of this inventionto preparehovel and valuable ingredients andto combine them withhydrocarbon lubricantoils to produce lubricants having high loadbearingcapabilities, to prepare such ingredi- 4o ents which have goodcharacteristics of stability, which are less corrosive, and which imparta greater influence when present in much smaller amounts than arerequired with extreme pressure ingredients now commercially available.Fur- 5. ther objects are the provision of methods oi making theingredient or ingredients, methods or preparing lubricantscontainingthese novel characterizing ingredients, and methods oflubrication 0 It is an important object of this invention to providemeans for satisfactorily inhibiting or preventing corrosion irom takingplace to a serious degree particularly in oilsoi relatively high vis- 5.tion to alter or modify a highly refined motor 0 oil, normallycorrosive, by the use of additive ingredient capable of substantiallyinhibiting this corrosion. It is a further object or this invention toprovide a substantially non-corrosive motor oil of high V. I. Stillanother object oi this invention is to provide an additive reagent oringredient capable of inhibiting the corrosive properties of these oils.The production of solvent reflned oils of low corrosive properties underconditions of automotive use is a major object of this invention, aswell as the method of production of such oils which combine a relativelyhigh viscosity index with arelatively low tendency to produce suchcorrosion. 7

this invention is the proin internal combustion engines, which do notdeposit gummy or resinous films or lacquers upon pistons, rings, valves,and cylinder walls of engines, and especiall those op rated atrelatively high temperatures and/or for long periods of time.

I have found that hydrocarbon oils of the classes defined above can bestabilized against the formation of acidic and/or corrosive and/orsludge bodies by the addition to said oils of a relatively small amountof a substantially stable, oil-soluble, water-insoluble reaction productof an' ester or phosphorous acid and an alkyl aroxy alkanbl. I have alsofound that novel lubricants having extreme pressure lubricatingcharacteristics can be produced by adding to oil a suflicient quantityof said reaction product. Among the esters of phosphorous acid which maybe suitably employed in the production or my reaction products are thearyl phosphites such as triphenyl phosphite, trinaphthyl phosphite,'trianthryl phosphite; the alkylated aryl phosphites such as thetricresyl phosphites, trixylenyl phosphites, trlethyl' phenylphosphites, tripropyl' phenyl phosphites, tributyl phenyl phosphites,triamyl phenyl phosphites, and the isomers and higher homologs thereof.While I prefer to employ the aryl phosphites in the production of myreaction products, I may also utilize the alkyl phosphites such astrimethyl phosphite, triethyl phosphite, tributyl phosphite, triamylphosphite, and the like. Mixed alkyl-aryl phosphites and hydroaromaticphosphites, as well as aryl or alkyl mono and diphosphites and theesters of hypophosphorous, pyrophosphorous, and thiophosphorous acidsmay also be employed. 7

The substituted alkanols which I utilize in the preparation of myreaction products are preferablythe alkyl aroxy alkanols having thegeneral formula R.CnH3n-a:.0.R'-OH, wherein R comprises hydrogen'or oneor more alkyl or substituted alkyl groups, preferablyalkyl groups havingat least 3 carbon atoms in the chain, Callas-3.0 comprises an aroxy orsubstituted aroxy group. R comprises one or more methylene orsubstituted methylene groups, and a: isat least 8. Typical of thesubstituted alkanols .are phenoxymethanol, propyl phenoxymethanol, butylphenoxymethanol, amyl phenoxymethanol, hexyl phenoxymethanol, heptylphenorwmethanol, and the higher homologues decyl, lauryi, cetyl, oleyl,and

stearyl phenoxymethanols. In lieu of the phenoxy group, other aroxygroups such as naphthoxy and anthroxy may be utilized, and in lieu ofthe methanol group, other alkanol groups such as ethanol, propanol,butanol, pentanol. and the like may be used. The substituted alkyl groupR and the substituted methylene group R may contain as substituentshalogen and/or sulfur.

The above mentioned substantially stable oilsoluble, water-insolublereaction products are adapted, as I have discovered, to be addeddirectly to or dissolved in a hydrocarbon oil for the purpose ofinhibiting or eliminating the normal tendency of said oils to corrodethe metaLbearingsand parts hereinbeiore mentioned, to stabilize saidoils againstthe accelerating action of metals on the deterioratingeffects of oxidation reactions under normal conditions of use and/orhandling and/or storage and to increase the ability of the oil towithstand high unit loadings. By substantially stable, I mean stableunder the normal conditions or use and/or handling and/or storage towhich these corrosion inhibitors and oxidation inhibitors are ordinarilysubjected, after manufacture, either before they are added to thehydrocarbon oil to be stabilized or after they are added to such an 011.

In preparing the reaction product to be employed in accordance with myinvention, I prefer to admix the ester of phosphorous acid with thealkyl aroxy alkanol and thereafter bring the mixture to a temperaturesufiicient to cause reaction of the ingredients, whereby there isintroduced into the ester of phosphorous acid at least one alkyl aroxyalkanol group. The mol ratio of ester to alkanol employed may vary fromabout 1:1 to about 1:25, and is preferably of the order of about 1:14.The admixture of ester and alkanol may be heated at atmospheric pressureunder a reflux condenser to a temperature suflicient to effect reaction,for example, temperatures of the order of from-about 200 F. to about 500F., and the resulting oil-soluble, water-insoluble reaction product maybe separated from the byproducts of the reaction by distillation underreduced pressure, or by recrystallization from a suitable solvent, or bywashing with a solvent having selective solvent power for either thereaction product or the undesirable by-products. Or, if the ester andthe alkanol are relatively high boiling, the reaction may be carried onat elevated temperatures of the order of from about 200 F. to about 350F., under reduced pressures of the order of m. m. or less. On the otherhand, if the ester and the alkanol are not relatively high boiling, thereaction may be carried on at elevated temperature and under a suitablesuperatmospheric pressure. Depending upon the ratio of ester to alkanolemployed, and upon the temperature and time of reaction, at least oneand in some instances two alkanol groups may be introduced into theester of phosphorous acid. In general, it is preferred that the alkylaroxy alkanol have a boiling point higher than that of the alcohol orphenol employed initially in the manufacture of the ester of phosphorousacid. The reaction products so produced may be regarded as complexesters of phosphorous acid which may or may not contain unreactedalkanol. Such reaction products have a wider range of utility andeifectiveness as inhibitors and the like than the simple esters fromwhich they are prepared.

Alternatively, my reaction product may be produced directly inhydrocarbon oil by adding thereto suitable quantities of ester andalkanol, and then heating the mixture to a temperature sufllcient tocause the reaction of the ester with the alkanol, undesirableby-products of the reaction being removed by distillation or by washingwith a suitable solvent.

The reaction products produced in accordance with my invention may beadded to hydrocarbon oils in varying amounts, depending uponthequalities it is desired to impart to the oil. For example, in orderto inhibit oxidation ofhydrocarbon oils such 'as lubricating oil,turbine oil, or electrical insulating oil such as transformer or cableoil, I may incorporate in the oil from about 0.05% to about 0.5% of myreaction products.

In the'case of lubricating oils for internal com-.

bustion engines, quantities of reaction product of the order of 0.1% toabout 0.7% will inhibit the formation of color bodies and acidity, andwill inhibit corrosion of bearing metals such as cadmium-silver andcopper-leadalloys. My reaction products, when employed in quantities ofthe order of 0.4% to about 0.7%, will inhibit the formation of sludge,resinous bodies, or "lacquers,"

and will impart to the oils moderate degree of film strength or extremepressure characteristics. Where a considerable degree of improvement infilm strength or extreme pressure characteristics is required, myproducts may be employed in amounts of the order of 1% to 2%, or more.In those cases where it is desirable, from an economic point of view, toemploy only sufficient quantities of my reaction products to inhibitoxidation of the oil, and to obtain a high degree of film strength bythe addition of other agents, I may add to the oil, for example, 0.4% ofmy reaction products and 0.6% of a film strength agent such as tricresylphosphate. Other film strength agents, of course, may be employed inlieu of or in addition to tricresyl phosphate, and the quantities ofsuch agents may be varied, as desired.

The reaction products of my invention may be utilized not only asinhibitors or film strength agents for hydrocarbon oils, but also forsimilar purposes in other products such as thickened oils or greases,cutting oils, petrolatums, waxes, animal and vegetable oils, or mixturesthereof with hydrocarbon oils.

What I claim is:

l. The method of producing an addition agent for hydrocarbon oils, whichcomprises reacting an ester of phosphorous acid with an alkyl aroxyalkanol at such temperature and for such period of time as to introduceinto said ester at least one alkyl aroxy alkanol group.

2. The method of producing an addition agent for hydrocarbon oils, whichcomprises reacting an arylester of phosphorous acid with an alkyl aroxyalkanol at such temperature and for such at least one alkyl aroxyalkanol group.

4. The method of producing an addition agent for hydrocarbon oils, whichcomprises heating an arylester of phosphorous acid with an alky aroxyalkanol at a temperature within the range of from 200 F. to about 500 F.for a period of time sufflcient to introduce into said ester at leastone alkyl aroxy alkanol group.

5. The method of producing an addition agent for hydrocarbon oils, whichcomprises heating at least one mol of an ester of phosphorous acid withfrom about 1 to 2.5 mols of an alkyl aroxy alkanol at a temperaturewithin the range of from about 200 F. to about 500 F. for a period oftime sufficient to introduce into said ester at least one alkyl aroxyalkanol group.

6. An addition agent for hydrocarbon oils consisting of an ester ofphosphorous acid corre-,

sponding to the formula R0 n'o r wherein R is an aryl radical, R is analkyl aroxy alkyl radical, and R" is of the group consisting of aryl andalkyl aroxy alkyl radicals.

RAYMOND REUTER.

' Patent Ne 2,5h9eh6 2 CERTIFICATE 'OF CORRECTIdN.

I 9 1- 1-6, RAYMOND REUTER.

It 1e hereb certified that error 'eare 1n.the pr1nt ed e eirieetioeofthe eboire mimbered patent requiring correction-es follows: Page 2,first column, 1 1ne 26-27 for the werd characterized. read--cheraeterizing--;

' page 5, first 001mm, line 11, for "about 1":lh" read --about 1:1.l|.-;and that the said Letters Patent should be read with tme'eeri-eetientherein that the sue me; conform t6 the record of the ease in the.Patent Office.

Signed. and sealed this 8th deg 01 August, A. 9'. 191m.

4 Leslie Frazer (Seal) Acting Commissioner of Patentie

